Drilling systems are employed for drilling wellbores into subterranean formations to retrieve hydrocarbon fluids, such as oil and natural gas. The drilling systems may comprise a drill string having a plurality of drill tools which may be used to carry out the drilling operation. For example, drill tools may be used to rotate a drill bit for drilling the wellbore. Drill tools also may be used for controlling the direction of drilling, for monitoring the drilling process, for supplying drilling fluid, and for a variety of other drilling related tasks. The drill string and drill tools may be used for successive drilling jobs, however difficulties arise in determining the health of a given drill tool, particularly while the given drill tool is downhole in a wellbore.